page_title: 2011 in the United States
section_title: April
hierarchical_section_title: 2011 in the United States / Events / April
caption_attribution_description: English: April 27 and April 28, 2011, brought the deadliest tornado outbreak in the United States since 1974. By dawn on April 28, at least 250 people had been killed in 6 states. Alabama was the hardest hit state, with 162 confirmed dead as of Thursday morning. This image shows the storms at 1:45 p.m. U.S. Central Daylight Time, and the animation shows the development of the weather system that spurred the widespread deadly tornadoes. The images are from the GOES satellite. The animation starts on April 26 and goes through the morning of April 28. The ingredients for severe weather are evident in the cloud patterns. Throughout the period, a relatively stable mass of cold air—visible as a swirl of more-or-less continuous clouds—rotates in the north along the top of the image. Meanwhile, moist air pushes north and west from the Atlantic and Gulf of Mexico. The warm air contains small low clouds. The collision between two such air masses is enough to generate severe weather, but the weather was amplified by the jet stream on April 27. Though not directly visible in the image, the narrow band of fast-moving wind that makes up the jet stream blew north and east between the two air masses. Surface winds blowing from the south and east and the jet stream blowing in from the west set up powerful smaller-scale circulations that generated lines of intense thunderstorms. The thunderstorms shown in this image began to rise over Louisiana midway through the day on April 27—around 16:00 UTC or 11:00 a.m. local time, and moved across Mississippi and Alabama through the afternoon. Forming along and ahead of the turbulent boundary between the two air masses, the storms are moving east and north with the jet stream. The bright white spots within the clouds are very active storms, quite probably the systems that generated tornadoes. Throughout the day, many such storms rose over the south. The slow eastward progression of the upper-level system permitted successive storms to affect the same region for a much longer time span than is typical. According to the National Weather Service, more than 150 tornadoes were reported throughout the day. The images in this animation are from the GOES satellite, a geostationary satellite whose orbit keeps it above the same spot on Earth at all times. Such an orbit allows the satellite to image the movement of clouds every few minutes, observations that are necessary for weather monitoring and forecasting. GOES is a joint NASA and NOAA satellite.
context_page_description: Events in the year 2011 in the United States.
context_section_description: April 3 – Crystal Mangum, the false accuser in the Duke lacrosse case, is arrested after repeatedly stabbing her boyfriend, Reginald Daye.
  April 4
  The U.S. Supreme Court upholds Arizona School Vouchers in a 5–4 ruling.
  In men's college basketball, the UConn Huskies defeat the Butler Bulldogs to win the 2011 NCAA Men's Division I Basketball Tournament.
  April 5
  Cuba and its partners announce plans to drill for oil in Cuban waters in The Gulf of Mexico.
  In women's college basketball, the Texas A&M Aggies defeat the Notre Dame Fighting Irish to win the 2011 NCAA Women's Division I Basketball Tournament.
  April 6 – A United States Navy F/A-18 crashes near Naval Air Station Lemoore in California, killing both crew members.
  April 8 – President Obama, House Republicans, and Senate Democrats agree on a week-long stopgap spending bill preventing a government shutdown resulting from a failure to pass the 2011 federal budget.
  April 10 – 2011 Masters Tournament: South African Charl Schwartzel won the 2011 event by two strokes over Adam Scott and Jason Day.
  April 13
  An Air France Airbus A380, operating as Air France Flight 007, collides with a Comair Bombardier CRJ-700, operating as Comair flight 553/Delta Connection Flight 6293 in Delta Connection livery, on a taxiway at John F. Kennedy International Airport in New York City. The double-deck Airbus A380 is the world's largest commercial passenger jet. The A380 had 520 people on board, and the smaller plane had 66. There were no injuries. The incident brings into question the spatial taxiway requirements for the new large A380's wingspan on existing airport taxiways.
  Reginald Daye dies 10 days after being repeatedly stabbed by Crystal Mangum, the false rape accuser in the Duke lacrosse case.
  April 14–16 – A tornado outbreak and severe thunderstorms kill at least 43 people across the Southern United States, with fatalities occurring in Oklahoma, Arkansas, Alabama, North Carolina, and Virginia. It is the deadliest U.S. tornado outbreak to occur in three years.
  April 18 – Standard & Poor's downgrades its outlook on long-term sovereign debt of the United States to negative from stable for the first time in history, citing "very large budget deficits and rising government indebtedness" as for why it did so. A statement from Standard & Poor's explained its reasoning; "We believe there is a material risk that U. S. policy-makers might not reach an agreement on how to address medium- and long-term budgetary challenges by 2013; if an agreement is not reached…this would…render the U.S. fiscal profile meaningfully weaker than [its peers]". This could possibly mean the US losing its AAA credit rating.
  April 25–April 28 – The most active tornado outbreak in United States history kills 339 people across the Southeastern United States, becoming the third deadliest tornado outbreak in United States history, falling behind the Tupelo-Gainesville tornado outbreak of April 1936 and the outbreak that produced the Tri-State Tornado of March 1925.
  April 27
  Responding to continued coverage by the mainstream media of Barack Obama citizenship conspiracy theories, that President Barack Obama was born on August 4, 1961, in Honolulu, Hawaii, Obama releases his long-form birth certificate.
  In an unprecedented meeting with reporters, the U.S. Federal Reserve chairman Ben Bernanke states that he expects less economic growth for 2011 as the economy has been weaker in recent months than he had thought it would be. Bernanke refused to speculate on when he would discontinue with The Federal Reserve's monetary stimulus policy, known as quantitative easing.
  Eight American troops and one contractor are shot and killed by an Afghan National Army Air Force pilot. Five Afghan soldiers were also wounded in the attack, for which the Taliban claimed responsibility.
caption: 2011 Super Outbreak – Satellite image of the storm on the evening of April 27 over the American Southeast
  339 total fatalities
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